The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) represents a major advance in cellular technology and is the next step forward in cellular 3G services as a natural evolution of Global System for Mobile communications (GSM) and Universal Mobile Telecommunications System (UMTS). The LTE physical layer (PHY) is a highly efficient means of conveying both data and control information between an evolved NodeB (eNB) and mobile entities (MEs), such as, for example, access terminals (ATs) or user equipment (UE). The LTE PHY employs some advanced technologies that are new to cellular applications. These include Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output (MIMO) data transmission. In addition, the LTE PHY uses Orthogonal Frequency Division Multiple Access (OFDMA) on the downlink (DL) and Single-Carrier Frequency Division Multiple Access (SC-FDMA) on the uplink (UL). OFDMA allows data to be directed to or from multiple users on a subcarrier-by-subcarrier basis for a specified number of symbol periods.
Examples of older wireless communication systems widely deployed to provide various types of communication content such as voice and data include Code Division Multiple Access (CDMA) systems, including CDMA2000, Wideband CDMA, Global System for Mobile communications (GSM), Universal Mobile Telecommunication System (UMTS). These wireless communication systems and LTE systems generally use different radio access technologies (RATs) and communication protocols, operate at different frequency bands, provide different quality of service (QoS) and offer different types of services and applications to the system users.
Various wireless communication protocols may be used for communications between ATs and access points (APs) of a wireless communication system. For example, the 1×RTT protocol as defined by the Telecommunication Industry Association (TIA) in the TIA-2000 series specifications may be used for voice and certain data transmissions on CDMA systems up to 144 KBps. For further example, a 1× Evolution, Data Optimized (1×EV-DO) as defined 3GPP2 CS0024-0, version 4 and subsequent versions of this standard may be used for data transmissions up to about 600 KBps. Various other transmission protocols may also be used. A particular AP or base station may support two or more protocols independently to enable separate or simultaneous use of different protocols by the same or different access terminals.
When moving between AP coverage areas, an AT in idle mode may detect a beacon periodically transmitted by an AP in a new coverage area to discover that wireless connectivity is available using a particular wireless communication protocol. For example, an AT may detect a 1×RTT beacon for an available 1×RTT connectivity and a Data Optimized (DO) beacon for an available DO connectivity. However, when in idle mode the AT may only wake up and be enabled to detect beacon signals at limited intervals. Accordingly, undesirable delay may be introduced between the time that an AT first moves into a coverage area for an AP and detection of a beacon enabling discovery of an available connectivity via the AP.
In addition, a new class of small base stations for providing access to wireless communication systems has emerged, which may be installed in a user's residence or business to provide indoor wireless coverage to mobile units using existing broadband Internet connections. Such a base station is generally known as a femtocell access point (FAP), but may also be referred to as Home Node B (HNB) unit, Home evolved Node B unit (HeNB), femto cell, femto Base Station (fBS), base station, or base station transceiver system. Typically, the femto access point is coupled to the Internet and the mobile operator's network via a Digital Subscriber Line (DSL), cable internet access, T1/T3, or the like, and offers typical base station functionality, such as Base Transceiver Station (BTS) technology, radio network controller, and gateway support node services. This allows a Mobile Station (MS), also referred to as a cellular/mobile device or handset, Access Terminal (AT) or User Equipment (UE), to communicate with the femtocell access point and utilize the wireless service. This new class of small base stations may be subject to certain hardware or resource limitations with respect to beacon signaling, and further may be deployed in an ad hoc (unplanned) fashion. Such factors may further complicate efficient detection of available beacons by ATs moving into a coverage area, or exacerbate delays in beacon detection.